How important is an oil catch can on our cars?

[Bretley]

We're talking about two different things.

-Blow-by will most likely be 100% burned off in the combustion cycle (unless you run a catch can that works to intercept it).

-Carbon Buildup cannot be solved by witchcraft, meth, catch cans or the such. Time and time again I've seen a new community that hasn't dealt with direct injection engines try all sorts of stuff to combat carbon build-up like Water/meth, catch cans, seafoam, voodoo, but when people pull off the intake manifold or use a borescope, it seems like a crap shoot.

To me, and obviously every single OEM car manufacturer has found it to not be worth it to run a catch can. Do they help in concept? Sure. Does throwing away a single gum wrapper that's in your pocket before race help in concept? Sure. But the benefits are so small they are basically null. Just my opinion.

So carbon build-up is not also caused by blow by? I'm trying to learn as well.

 

[Bretley]

I figured that manufacturers don't do things like this because it's gotta be emptied frequently and that crap isn't gonna pass any 100k emissions test lol.

 

[M-Sport fan]

I figured that manufacturers don't do things like this because it's gotta be emptied frequently and that crap isn't gonna pass any 100k emissions test lol.

...and MOST customers will not be bothered to empty it, or be willing to pay someone else to empty it.

Also, even if it does not even slightly slow down the valve cleaning requirements of D.I., I figure that oil mist in the combustion chamber at the very least, reduces the octane of the fuel mixture somewhat (yes, even if it is only 'minutely', WHO wants THAT?!?).